The present invention is a reactive elastomeric block co-oligomer comonomer and lactam-block co-oligomer copolymers derived therefrom. The present invention includes methods to make the block co-oligomer and the copolymers.
The anionic polymerization of lactams such as caprolactam is known to proceed through the use of two solutions, as for example in U.S. Pat. No. 3,017,391 of Mottus, et al. (1962). The first solution contains molten caprolactam in which is dissolved an alkali metal or alkaline earth metal-containing material which, in situ, causes the formation of a caprolactamyl anion. The active catalyst may thus be lithium or sodium caprolactam or may be bromomagnesium caprolactam or similar ionic compounds. The second solution contains molten caprolactam in which is dissolved a co-catalyst, which in the above patent may be an acyl biscaprolactam such as terephthaloyl bis(caprolactam). Mixing solutions under appropriate temperature conditions causes polymerization to form a polyamide having at some intermediate point in the chain a terephthaloyl moiety between amine ends of polyamide chains, having caprolactamoyl or carboxy end groups and, in most instances, some degree of branching such as at the nitrogen of an amide ligand.
Molded parts can be prepared by reaction injection molding. A reactive mixture containing caprolactam or similar lactam monomers is injected into a mold where the reaction takes place. While such processes may proceed through anionic polymerization using similar catalysts and co-catalysts to those described above, it is generally desired to achieve faster cycle times at higher temperatures and to obtain parts with modified properties, and especially increased impact strength, compared to those prepared by the processes described above.
U.S. Pat. No. 3,366,608 discloses polymerizing caprolactam in the presence in an alkylene catalyst, N,N'-diacyl biscaprolactam and a polyamine containing two or more primary or secondary amine groups per molecule, or a polyol containing two or more hydroxyl groups per molecule. Suitable polyols are indicated to include diethylene glycol, trimethylol propane, and polyglycols such as polyethylene glycol and polypropylene glycol.
U.S. Pat. Nos. 3,862,262; 3,993,709; 3,944,629; 4,034,015; and 4,487,920 disclose many useful polyols which can be polymerized with caprolactam to form lactam-polyol containing polymers. These patents are hereby incorporated by reference.